Hydraulic press construction



July 28, 1959 R. v. ROWLES ET AL HYDRAULIC PRESS CONSTRUCTION 2 Sheets-Sheet 2 Filed Aug. 2'7, 1956 INVENTORS REGINALD VICTOR ROM/LE6 BERTHAM THOMAS GUM/1V6 vention;

United States Patent 2,896,581 HYDRAULIC PRESS CONSTRUCTION Reginald Victor Rowles and Bertram T. Gowing, Gloucester, England, assignors, by mesne assignments, to Anglo-American Extrusion Company, a corporation of Delaware Application August 27, 1956, Serial No. 606,343

Claims. (Cl. 12138) This invention relates to hydraulic press constructions, and more particularly to hydraulic presses of the kind including multiple cylinder and ram or piston-assemblies in which cylinders and ram or piston parts may be coaxial. Constructions embodying the present invention are of general application and utility when incorporated in presses of the general class referred to, and may, for example, be ,used to particular advantage in press ap-' paratus of the kind disclosed in the co-pending application of Reginald Victor Rowles, Robert Madeley, and

Bertram Thomas Gowing, Serial No. 295,097, filed June As in any other hydraulic press construction, the fluid seals or packings of multi-cylinder presses require repair, replacement or adjustment from time to time. In many previously known presses such seals or packings have not been readily accessible. One object of the present invention is to provide a press construction of the class referred to in which the cylinder and piston or ram elements are so constructed and relatively arranged that the'packings or seals are readily accessible for servicing. Another object of the invention is to provide a press apparatus including a fluid communication pipe so mounted and hydraulically connected to the press as to avoid stressing the pipe when the press elements, e.g., the cylinder or cylinders, the ram orpiston parts, and

the frame or base are strained as an incident to press adjusting the position of an auxiliary, e.g., a pre-stroke ramor piston relative to a main or power ram to which thejauxiliary ram is fixed.

Other objects will become apparent from a reading of the following description of a preferred embodiment of the invention, the appended claims, and the accompanying drawings, in which:

Figure 1, is a view partly in vertical section and partly in elevation of a press construction embodying the in- Figure 2 is a top plan view ofthe construction shown in Figure 1; g 1 I Figure 3 is an enlarged scaletransverse vertical sec tional view on theline 33 of Figure 1;' 4

Figure 4 is an enlarged scale transverse vertical sectional view on the line 44 of Figure 2; and

Figure 5 is a fragmentary vertical section on the line 5-5 of Figure 2, drawn on an enlarged scale. The illustrative embodimentof a press constructed in accordance with the invention is shown as being carried by a supporting base, generally designated A, comprising longitudinally extending spaced pairs of girders 1 supported on transversely disposed joists 2 resting on a foundation bed 3. The press structure includes two cylinder block 4 and 5 connected in horizontally spaced relation by tie bars 6 extending through the cylinder blocks,

adjacent faces of the cylinder blocks.

'ice

and spacing sleeves 7 interposed between the inner and blocks and being connected at their lower ends to the underlying joists 2' as shown in Figure 3, serving to anchor the frame assembly to the base A.

The cylinder blocks 4 and 5 are formed respectively with axially aligned cylinders 14 and 15, the mutually adjacent inner ends of which are spaced axially from each other. Mounted for reciprocation in the cylinders 14 and 15 is a unitary piston or ram structure, generally designated 16, comprising end parts 16 and 16 which extend into the inner ends of the cylinders 14 and 15 respectively, the piston part intervening between the through the outer end of the cylinder 15 is a tail rod 19.

The piston rod 17 and the tail rod 19 are of lesser diameters than their respectively associated piston parts 16* and 16 so that annular working faces 16 and 16 are provided at opposite ends of the piston structure 16 and within the cylinders 14 and 15.

Fluid may be admitted under pressure to and exhausted from the cylinders 14 and 15 in any suitable manner so as to effect working movements of the piston structure, to the left as viewed in Figure 1, and retracting movements, to the right as viewed in Figure l. The confaces.

struction shown is especially adapted for operation of the piston structure by fluid delivered under the same unit pressure to both the cylinders 14 and 15, for example, in the manner disclosed in the co-pending application of Reginald Victor Rowles et al., Serial No.

295,097, filed June 23, 1952, previously referred to. For the operation of a press in the manner disclosed in the co-pending application, it is required that the piston or ram structure have opposed differential area working Such a relation is established in the construction shown in the accompanying drawings by the provision of cylinders 14 and 15 and piston parts 16 and 16 of equal diameters, and by forming the piston rod 17 of rel- In conse-' quence of this relative dimensioning, the working face 16 of the piston part 16 is of relatively larger area than the working face 16 of the piston part 16 Escape of pressure fluid from the outer end of the cylinder 14 is prevented by packing 20 held in place by a packing ring 20 secured in any suitable manner to the outer end of the cylinder block 4. Similarly, packing 21 at the outer end of the cylinder 15 is heldjin place by a ring 21 secured to the outer face of the cylinder block 5 and seals the end of the cylinder 15 against the escape of fluid under pressure.

In accordance with the invention, the inner ends ofthe cylinders 14 and 15 are sealed against the escape of pressure fluid by packings 22 and 23 respectively held in place by rings 22 and 23*, secured in any desired manner to the adjacent inner faces of the cylinders 14 and 15,

The tie bars 6 The rings 22 and 23 may be split or composed of segments to facilitate assembling and disassembling. The arrangement is such that the rings 22 and 23 and the associated packings 22 and 23 are readily accessible. through the space between the cylinder blocks'4 and 5. Thus, although a unitary piston structure spans the space. between the. inner faces of the separate, axially aligned cylinders 14 and 15 and has parts operable respectively in. these, cylinders, the packingswhich seal the inner ends of the cylinders may readily be reached for adjustment or servicing.

During a retracting stroke of the composite ram structure, fluid underpressure is admitted to the cylinder 14.

fluid under pressure is supplied within the cylinder 15. t0.

act upon the ram surface 16 and the cylinder 14 is connectedto exhaust.

The valve mechanism for controlling the introduction of pressure fluid to and the exhausting of fluid from the cylinders 14 and 15 may be of any suitable kind and hence as is illustrated at 24 only diagrammatically in Figures 1 and 2 as being supported on the foundation 3- beyond the right end of the press. An inlet pipe. 25 connected to the valve structure 24 and to a source of fluid under pressure, not shown, provides for the introduction of pressure fluid to the cylinders 14 and 15 under the control of the valve mechanism 24; and an exhaust pipe 26 connected to the valve mechanism 24 provides for the exhausting of fluid from the cylinders 14- and 15.

In accordance with the invention, the piping connecting the valve mechanism 24 and the cylinders 14 and 15 may be so constructed and arranged as to prevent or minimize stressing of the piping as an incident to operation-effected straining movements of the cylinder blocks 4 and and. other frame parts, eg the tie rods 6. In the illustrated embodiment, an inlet pipe 27 has its right hand end stationarily mounted by being fixedly connected to the valve.

structure 24, and has its left hand end mounted for slidingmovement in a bore 28 extending horizontally through a boss29 depending from the cylinder block 4, packings or seals 30, 30 at opposite ends of the bore 28 sealing the latter against the endwise escape of fluid between the bore wall and the pipe 27. A plug 31 secured in the extreme left end of the pipe 27 blocks off the latter against the escape of fluid. Communication between the pipe 27 and the cylinder 14 is provided by ports 32 in the pipe registering with "a passage 33 extending from the interior of the cylinder 14 to the bore 28, the passage 33 having an annular recess part 33 extending around the pipe 27 for providing communication between the passage and.

substantially the entire circumference of the pipe.

. The pipe connection between the valve mechanism 24 and the cylinder 15 is similar to that between the valve 24, and the cylinder 14, just described. As shown, a pipe, 34 has its. right end stationarily mounted by being fixedly connected to the walve structure 24 and extends under the press structure and through a boss 35 depending from the cylinder block 5. A passage 36 provides communica tion between the cylinder 15 and ports 37 in the pipe 34, the extreme left end of which is closed by a plug 38.

In operation, when the press structure is stressed longitudinally under load, causing it to be strained with consequent relative movement of the parts longitudinally of the ram structure axis, the relative movement between thecylinder blocks 45 and the valve structure 24 can take place without harmfully stressing the pipes 27 and 34, since the latter are mounted for free sliding movement.

respectively in the cylinder block bosses 29' and35.

, The, press shownin thev drawings is also equipped with.

an auxiliary power saving or pre-stroke ram 40 connected to the ram structure previously described for supplementing the action of the ram face 16 for example while the ram structure is performing an approach stroke before engagement of the tool with the workpiece. The pre-stroke ram 40 is mounted for reciprocation in a prestroke cylinder 41 axially aligned with the cylinders 14 and 15 andsecured in the cross head 9 by retaining rings 42 and 43. The pre-stroke cylinder 41 has its inner end relatively adjacent to, although spaced somewhat from, the cylinder 5, and has its outer end relatively remote from the cylinder 5. For connecting the pre-stroke ram 40 to. the tail rod 19 of the main ram structure, the prestroke ram is formed with a reduced threaded end projection or portion 44 which extends through and'has threaded engagement with a split adjusting nut part 45 secured to the tail rod 19 by a locking ring 46 the inner portion of which overlies a flange 47 on the'nut 45. The

locking ring 46 is secured to the right end of the tail rod.

nection with the preastroke ram extension 44 for assisting.

in maintaining the pre-stroke ram and the'main ram struc ture in axial alignment.

Normally, the halves of the split nut 45 are clamped into binding engagement with the threaded portion 44 of the pre-stroke ram 40 by screws 51. To enable axial adjustment of the pro-stroke ram 40 relative to the main ram structure, the screws 51 may be loosened so as. to permit rotation of the ram 40 and its extension 44 relative to the nut 45, thereby to displace the pre-stroke ram 40 axially relatively to the main ram structure. Such axial adjustment is. useful for determining the limiting of retracting movement of the main ram structure effected. by engagement of the right end of the pre-stroke ram 40 with the adjacent end, that is the outer end, of the prestroke cylinder 41. Turning of the pre-stroke ram 40 for effecting such an adjustment may easily be accomplished with the aid of handles 52 projectingradially from the. ram 40. After the desired adjustment has been efiected, the screws 51 are, of course, tightened so as again to clamp the threaded end 44 of the pre-stroke ram and hold it in adjusted position.

For enabling convenient adjustment of the limit of. working strokes toward the left, a stop collar 53. is mounted in threaded engagement with a threaded end part. 54 of the tail rod 19, and is positioned so as to be engage able with an abutment ring 55 mounted on the right end. of the cylinder block 5 and surrounding and extending axially to the right of the sealing ring 21 By turning the collar 53- on the threaded part 54 of the tail rod 19.

and thus displacing the collar 53 axially with respect to the tail rod, the limit of leftward travel of the entire ram structure can be variably determined. For locking the collar 53 against rotation in adjusted position, it is formed with a plurality of circumferentially deployed. holes 56 adapted to receive locking pins 57 extending to the left from the locking ring 46. Rotation of the collar 53, with the locking pins 57 withdrawn, is facilitated by radially projecting handles 58.

. Pressure fluid is introduceable into and exhaustible from the power saving cylinder 41 by a pipe 59 con nected to. any suitable valve mechanism, not shown, adapted to control communication of the pipe 59 selectively with a source of fluid pressure and with an exhaust. Before commencement of a typical operating cycle, the ram 40 and piston parts 16*, 16 will be in the positions shown in Figure 1, that is in their retracted positions, with fluid under pressure acting through the pipes 27 and 34 and on the ram surfaces 16 and 16, the: pre Stroke cylinder. 41 being connected to exhaust through the pipe 59. To initiate. an. approach stroke, fluid. under pressure is introduced through the pipe 59 into the pre stroke cylinder 41 to act upon the pre-stroke ram 40. The aggregate area of the working faces of the ram 40 and ram or piston surface 16 being greater than the area of the ram or piston surface 16, the entire ram structure will travel to the left, forcing fluid under pressure from the cylinder 14. At a predetermined point in the left* Ward travel of the ram structure, for example when the tool carried by the piston rod 17 has engaged or is just about to engage the work, the valve mechanism 24 is operated to connect the cylinder 14 to exhaust while maintaining the cylinder 15 connected to the pressure source. Under these conditions, the leftward movement of the ram structure will not be opposed substantially by fluid acting on the ram face 16 so that the remainder of the working stroke will be performed with the full power available. I

It will be appreciated that during a working stroke the press structureis subjected to different stress conditions, one during the pre-stroke ram travel when the cylinder 14 is pressurized, and another during the latter part of the stroke, that is the main working stroke, when the cylinder 14 is connected to exhaust; and that during a retracting stroke still another stress condition exists in that the cylinder 41 is connected to exhaust instead of being pressurized. If desired, the cylinder 15 may also be connected to exhaust during the retracting stroke. It follows that under the three or four different stress con ditions, the cylinder blocks 4 and 5 will move axially,

even if only slightly, to different positions relative to the fixedly mounted valve structure 24. Because of the sliding mounting of the pipes 27 and 34 relative to their associated cylinder blocks 4 and 5, these strain movements of the cylinder blocks will not materially strain the pipes, so that there will be no danger of operationelfected breakage of the pipes or loosening of connections.

The construction disclosed embodies the invention in a preferred form, but it is intended that the disclosure be illustrative rather than definitive. The invention is defined in the claims.

We claim:

1. In a hydraulic press, a frame; two axially aligned horizontal cylinders mounted on said frame with their adjacent inner ends spaced axially from each other; a unitary piston structure comprising a first piston part extending through the inner end of one of said cylinders and being reciprocable therein, a second piston part extending through the inner end of the other of said cylinders and being reciprocable therein; a piston rod projecting outwardly through the outer end of said one of said cylinders, and a tail rod projecting outwardly through the outer end of said other of said cylinders; packings in the inside walls of said cylinders adjacent to the inner ends thereof and being accessible for servicing through the space between said cylinder inner ends; a third cylinder mounted on said frame in axial alignment with and spaced outwardly from the outer end of said other of said cylinders, said third cylinder having an inner end relatively adjacent to said other of said cylinders and an outer end relatively remote from said other of said cylinders; a pre-stroke ram reciprocable in said third cylinder and projecting towards said other of said cylinders; means connecting the projecting part of said pre-stroke ram to the outer end of said tail rod for relative axial adjustment, said pre-stroke ram being engageable with said outer end of said third cylinder for limiting movement of said pro-stroke ram and said unitary piston structure, and the axial adjustment of said pre-stroke ram relative to said unitary piston structure determining selective limits of movement of said unitary piston structure;'a pipe extending under said cylinders parallel to the common axis thereof; means stationarily mounting one end of said pipe; a bore in one of said cylinders receiving a portion of said pipe remote from its stationarily mounted end for relative sliding movement; and a passage extending from the interior of said one of said cylinders to the interior of the portion of said pipe.

which extends through said bore, the relative sliding movement of said pipe and said bore permitting operation effected straining movement of said one of said cylinders without stressing said pipe.

2. In a hydraulic press, first and second axially aligned cylinders having equal internal diameters; means mounting said cylinders with their adjacent inner ends axially spaced from each other; a piston structure comprising a first piston part extending through the inner end of said first cylinder and being reciprocable therein, said first piston part having a pressure face area enclosed by said first cylinder, and a second piston part extending through the inner end of said second cylinder and being reciprocable therein, said second piston part having a pressure face area enclosed by said second cylinder opposed to and less than the pressure face area of said firstpiston part; a third cylinder axially aligned with said first and second cylinders; a third piston part projecting outwardly from said second piston part through the outer end of said second cylinder and into said third cylinder, said third piston part having a pressure face area enclosed by the third cylinder and being such that when added to the pressure face area of said second piston part, the added areas together exceed the pressure face area of said first piston part; a stop collar adjustably mounted on said third piston part and being engageable with a part at the outer end of said second cylinder for limiting movement of said piston structure; locking means secured to said third piston part and cooperative with said stop collar for maintaining the latter in adjusted position; and packings in the walls of said first and second cylinders adjacent to the inner ends of said first and second cylinders and being accessible for servicing through the space between the inner ends of said first and second cylinders.

3. A hydraulic press construction as set forth in claim 2 in which said first and second cylinders are stationary except for being movable slightly incidentally to operation-elfected straining, said construction including a pipe extending parallel to the common axis of said cylinders; means stationarily mounting one end of said pipe; a bore in one of said cylinders receiving the opposite end portion of said pipe for relative sliding movement; and a passage extending from the interior of the portion of said pipe which extends through said bore to the interior of. said cylinder, the relative sliding movement of said pipe opposite end portion and said bore permitting slight operation-effected straining movement of said one of said cylinders without stressing said pipe.

4. In a hydraulic press, two axially aligned cylinders; means mounting said cylinders with their adjacent inner ends axially spaced from each other; a piston structure comprising a first piston part extending through the inner end of one of said cylinders and being reciprocable there in, and a second piston part extending through the inner end of the other of said cylinders and being reciprocable therein; packings in the walls of said cylinders adjacent to the inner ends of said cylinders and being accessible for servicing through the space between said cylinder ends; a third piston part projecting outwardly from one of said two piston parts through the outer end of the associated cylinder; a stop collar adjustably threaded on said third piston part and being engageable with a part at the outer end of said associated cylinder for limiting movement of said piston structure; a locking ring secured to said third piston part; and locking pin means extending from said locking ring and into selected openings in said stop collar for maintaining the latter 'in adjusted position.

5. In a hydraulic press, two axially aligned cylinders of substantially equal diameters; means mounting said cylinders with their adjacent inner ends axially spaced from each other; a piston structure comprising a first piston part extending through the inner end of one of said cylinders and being-reciprocabl'e therein, and asecond piston part of substantially the same diameter as said first piston part'extendingthrough the inner end of the other of said 1 cylinders and'being reciprocable therein; packings in the walls of said cylinders adjacent to the inner ends of said cylinders and being accessible for servicing through the space between said cylinder inner ends; a first" rod projecting outwardly from one of said piston parts through the outer end of the associated cylinder; a second rod projecting outwardly from theother of said piston parts through the outer end-of the other of said cylinders and being of a diameter difierent from the diameter of said first rod'whereby differential area piston working faces are respectively presented bysaid first and second piston parts in their associated cylinders; a third cylinder aligned axially with said other of said cylinders and positioned outwardly beyond the latter, said third cylinder having an inner end relativelyadjacent to said other of said cylinders and an outer end relatively remote from said other of said cylinders; a prestroke ram extending axially outwardly from said second rod in fixed relation thereto and being reciprocable in said third cylinder, the outer end of said pre-stroke ram being engageable with said outer end' of said third cylinder forlimiting outward movement of said piston structure; an'externa-lly threaded axialprojection on said pre-stroke ram; an internally threaded split nut on said second'rod receiving said eX ternaI'l'y threaded" projection for axial" adjustment whereby to vary the limit of movement of said piston structure deter-mined by engagement of the outer end-' of said. pre'-- stroke rain with said outer endof said third cylinder; and means for locking said split nut in clamped'threaded' engagement with said externally threaded projection.

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